This invention relates generally to devices for transferring fluid and, more particularly, to a medical coupling device which effectuates fluid transfer from one fluid reservoir to another in a manner that tends to avoid undesirable exposure to the fluid.
In the medical environment, it is often necessary or desirable to collect a sample of fluid, such as a liquid or gas, or to transfer a sample of such fluid from one reservoir to another while still preserving the integrity of the sample. For example, it is often desirable to collect a sample of blood from a patient and then transfer this sample to a reservoir, such as an evacuated tube or culture media container, for evaluation, testing or processing. A variety of devices have been developed that effectuate the collection and transfer of fluid between reservoirs. These include medical coupling devices and hypodermic needles.
Medical coupling devices employed for this purpose typically have a shroud or sheath which surrounds a pointed cannula or needle that in turn pierces an injection site on a rubber septum or diaphragm which is sealingly attached over an opening in the reservoir to which the fluid is to be transferred. The shroud also covers a sufficient portion of the reservoir such that the cannula or needle can properly pierce the injection site and transfer fluid to the reservoir from another reservoir to which the device is connected. While such devices effectuate fluid transfer between reservoirs, they do have disadvantages. Although the pointed cannula or needle is shielded by the shroud, the risk of accidental needlesticks still remains if, for example, a finger is inadvertently inserted into the open end of the shroud and contacts the pointed cannula or needle. Although the risk of accidental needlesticks has for many years been of concern to the medical community, it has been accentuated by the increasing prevalence of Acquired Immuno Deficiencies Syndrome (AIDS) among patients and the life threatening consequences associated with the unwanted transfer of the AIDS virus, hepatitis and other diseases.
The aforementioned disadvantage also tends to be exacerbated by the fact that medical coupling devices of this nature are used in combination of a variety of differently dimensioned and shaped reservoirs which the shroud needs to cover. It is also desirable that the shroud be large enough to permit the reservoir to come in contact with the needle so that the needle can pierce the injection site of the septum. There are, thus, constraints on the degree to which the shroud can be configured to reduce the risk of accidental needlesticks. Problems can also arise when the user attempts to disconnect and remove a reservoir which is large enough to engage the interior of the shroud, thereby creating a suction force which may need to be overcome during removal.
Other medical coupling devices also exist which utilize a cannula that is slidably received in a slit of an already pre-slit septum or diaphragm. These devices, however, are fundamentally incompatible with the wide variety of reservoirs on the market that do not have pre-slit septums or diaphragms. Further, the manufacture of devices containing pre-slit septums or diaphragms tends to be more expensive and complicated than for their slit-less counterparts.
Hypodermic needles have, of course, been utilized for years to conveniently and cost effectively transfer fluid between two reservoirs. To that end, a number of different types of reservoirs have been fashioned that include an injection site which is sealed by a diaphragm and which can be sealingly pierced by a hypodermic needle. Such reservoirs included evacuated tubes, medication vials, culture media containers, IV lines, wide-sites, catheters and the like. However, hypodermic needles pose serious risks of accidental needlesticks to medical personnel, especially where the needles have been exposed to patient fluids that contain the agents of diseases like hepatitis or AIDS.
It should, therefore, be appreciated that there exists a definite need for a medical coupling device which efficiently and effectively accomplishes fluid transfer from one fluid reservoir to another in a variety of situations in a manner that tends to reduce the risk of this exposure to unwanted diseases, infectious agents, contaminants and the like.